Distance-finder.



Patented Jan. 2, I900.

R. L. MARSHALL.

DISTANCE FINDER.

(Application filed May 27, 1899.)

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No. 640,679. Patented Jan. 2, I900. R. L. MARSHALL.

DISTANCE FINDER.

(Applibation filed m 27, 1899.) (No Model.) 2 Sheets-Sheet 2v UNITEDSTATES PATENT 'nrrcn.

ROBERT L. MARSHALL, OF ELlZABETI-ITOWN, KENTUCKY, ASSIGNOR OF ONE-FOURTHTO A. C. LARKIN PERCEFULL, OF SAME PLACE.

DISTANCE-FINDER.

SPECIFICATION forming part of Letters Patent No. 640,679, dated January2, 1900. Application filed May 27, 1899. Serial No. 718,548. (No model.)

To all whom it may concern:

Be it known that I, ROBERT L. MARSHALL, of Elizabethtown, in the countyof Hardin and State of Kentucky, have invented a new and usefulImprovement in Distance-Finders, of which the following is aspecification.

The object of my invention is to provide a simple, practical, andaccurate instrument for finding the distance or range of any remoteobject at once by a simple adjustment without any calculation orcomputation whatever. It belongs to that class of instruments in whichtwo telescopes are fixed at opposite ends of a base-line, and one ofsaid telescopes is made adjustable to sight along the hypotenuse of aright-angled triangle, this adj ustable telescope being connected bygears with an index-hand which registers on an amplified scale thedistances for the varying angles formed by the hypotenuse when alinedupon objects at varying distances.

My invention consists in the peculiar construction and arrangement ofthe parts of an instrument operating on this principle and designed togive more accurate results than have heretofore been obtained.

Figure l is a plan View of the instrument. Fig. 2 is a diagram showingits mode of use. Fig. 3 is a View of the adjusting devices with thegraduated dial removed. Fig. 4 is an edge view of the gears shown inFig. 3, and Figs. 5 and 6 show modifications.

In the drawings, A represents any suitable table-surface, on which ismounted a frame consisting of the part B, representing the baseline ofthe right-angled triangle, a bar B rigidly fixed to the base-line and atright angles to it, and the bar B, which is jointed at L to thebase-line bar B, so as to swing at varying angles to the bar B Thebase-bar B is preferably about five feet long, so as to give a base-line of suitable length. On the bar 13 is mounted in alinement thetelescope D,,and on the movable hypotenuse-bar B is mounted anothertelescope D, fixed to the bar Bin alinement therewith and movable withit.

In use the movable telescope D, base-line B, and fixed telescope Doccupy the position shown in the diagram Fig. 2, in which it will beseen that objects remote from the telescope when sighted by thetelescope D will require the movable telescope D to be adjusted at thevarious angles 1 2 3 in order to intersect the object. This movement oftelescope D is made to register on a graduated scale the distances, sothat all that it is necessary to do is to sight the telescope D on theremote object, then adjust the telescope D until it also sights theobject, and then to read off on a scale the position of a pointer orindex-hand which has been moved by the adjustment of the telescope D,and this position of the index-hand indicates at once withoutcomputation the distance of the object. Instruments operating on thisprinciple have heretofore been constructed; but the means which I employfor transferring the movement of the hypotenuse-bar or movable telescopeto the index-hand comprehend a new principle that adds great accuracyand efficiency to the instrument, which I will now describe.

K, Fig. 1, is a shaft arranged in hearings on the table-surface inparallel position to the arm 13 of the frame and bearing at one end aturning-crank X and at the other having a screw-threaded end in, that istapped through a nut m, having an accurate interior thread fitting thescrew-threaded end It of the rod K. This nut m is jointed to atoggle-bar M by a swiveling plate m, and the toggle-bar at its other endis jointed to an offset on the h ypotenuse-bar B.

F is a quadrantal segment having on its are fine teeth of uniform sizeaccurately cut. This segment is fulcrumed in a fixed frame-plate G.

E is a pin or roller mounted on the movable hypotenuse-bar B andarranged to bear against a projection f of the segment on the oppositeside of the fulcrum from the teeth.

The bearing-face on the side of the projection pinion h is arranged inmesh with a series of teeth on a springbarrel J. I is a second smallerdial with an index-hand i, that is fixed to a notched disk i which hasten notches in it, and into which there works a log or tappetarm i fixedto the pinion or shaft of the large index-hand h. The purpose of this isto cause each revolution of the large index-hand h to register itself onthe small dial by moving its hand one space. This extends the range ofthe instrument to ten times the number of subdivisions on the largerdial.

Now in pointing out with greater distinctness the principle of myinvention it will be noted by reference to Fig. 2 that as the objectbecomes more remote the movable telescope is adjusted to a position morenearly parallel with the other telescope D. In Fig. 1 this isaccomplished by turning the shaft K so as to draw the nut m toward theobserver. This in bringing the togglearm M to a position more nearly atright angles to the shaft K projects the bar B and telescope Doutwardly, as shown by dotted lines, and the pin orroller E, acting onthe extension fof the segment F, deflects the latter,and so turns theindex-hand h. It will be observed, however, that as the toggle-arm Mapproaches the right-angular po.

sition to shaft K the moving effect of arm M has a constantly-increasingpower on bar B, but diminished speed or throw on the same, while in theeffect of the pin or roller E on the segment F just the reverse takesplace-that is to say, the action of pin E in approaching the center ofsegment F is to exert a constantly-diminished power, but increased speedor throw for the segment F. In other words, the action of M upon B iswith a constantlyincreased power and diminished speed,while the actionof E upon F is with a constantlydecreasing power, but increased speed orthrow, and these two factors may be so adjusted as to allow the dial IIto be spaced oif with equal graduations, which is a feature of greatimportance in securing accurate results in an instrument of this class.

To prevent loose motion at the point of articulation of bar B with thebase-bar B, a spring 0 is made to press constantly upon the same.

An adjusting-crank Y is provided, which by suitable mechanism (notshown) is made to adjust the frame B B B up or down, and another crank Zserves to adjust the instrument to the right or left. These features,however, are common, and as they form no novel part of my invention itis not necessary to show or describe them in detail.

As modifications of my invention the smooth and sliding'contact betweenthe bearing points E and f may, as in Fig. 6, be replaced by aneccentric toothed segment E, meshing with a volute spiral gear f onsegment F and having the same principle of differential leverage, itbeing understood that the bar B is moved by a toggle-link M.- (Seen inFig. 1.) I may also in instruments of short range dispense with theenlarged toothed end of segment F, as seen at F, Fig. 5, and preserveonly its fulcrum-shaft and extension f and mount index-hand h directlyon the fulcrumshaft of the extension f, in which case the grad uateddisk is concentric with the fulcrumshaft of the extension f.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. In a rangefinder having a base-line, a stationary telescope at rightangles thereto, and a movable hypotenuse-bar jointed thereto and havinga second telescope; of means for adjusting the hypotenuse-bar,comprising a laterally-adj usting device for the same which has avariable throw or range of deflection, an index-hand and dial, andmechanism between the ind cx-hand and the hypotenuse-bar which also hasa variable throw or range of movement the variable throw of one of theseparts being reverse to that of the other in respect to the relation ofspeed and power subsiantially as and for the purpose described.

2. In a range-finder, the combination of base-line bar, a stationarytelescope at right angles thereto, and a movable hypotenuse-bar jointedthereto and bearing a second telescope, means for adjusting thehypotenusebar consisting of a screw-shaft, a nut, and a toggle-arm, agraduated dial with index-hand bearing a pinion, a toothed segmenthaving a stationary fulcrum and meshing with said pinion aud having alsoan extension f, and a bearing-surface on the hypotenuse-bar adapted toact against the extension f substantially as and for the purposedescribed.

3. In a range-finder, the combination of a base-line bar, a stationarytelescope at right angles thereto, and a movable hypotenuse-bar jointedthereto and bearing a second telescope, means for adjusting thehypotenusebar consisting of a screw-shaft, a nut, and a toggle-arm, atoothed segment having a stationary fulcrum and an extension f, abearingsurface on the hypotenuse-bar adapted to act upon the extensionf, an index-hand 72, with pinion meshing with the segment, a spring forrestoring the hand and segment to its position of rest, a graduateddial, and a smaller supplementary dial with index-hand connected by adiminishinggear with the index-hand of the large dial substantially asand for the purpose described.

ROBERT L. MARSHALL.

Witnesses:

Enw. W. Bren, H. C. LARKIN PERCEFULL.

